Abort mechanism

ABSTRACT

A fuze having an arming means, an actuating means, a firing mechanism, an abort catch, and a detonating means. The abort catch of this fuze is capable of preventing the detonation of the fuze under any premature impact. This abort action can take place at any time subsequent to removal of the safety pin and prior to the time the fuze is fully armed.

United States Patent 7 1151 3,706,282

Lohmann et al. 1 51 Dec. 19, 1972 [5 1 ABORT MECHANISM 2.924J76 2/l960 Neuwirth. Jr. cl =11 ..1o2/71 2.981.192 4/1961 Grandy 102 711 [72] Inventors: Arthur M. Lohmann, Hopkins; King Spurbeck, Golden Valley; Raymond H. Burg, Minnetonka, all of Minn.

[73] Assignee: The United States of America as Primary Examiner-Samuel w. Engle represented by the Secretary of the Attorney-Harry A. Herbert, Jr. and Jacob N. Erlich Air Force 221 Filed: Jan. 21, 1970 57 ABSTRACT 21 Appl. No.: 4,643

3.022.733 2/l962 Junghans l02/7l A fuze having an arming means, an actuating means, a

52 us. c1. ..l02/76 R, 102/78 [511 1111.0. ..F42c 15/00 means- The catch "1' fule capable of [58] Field of Search ..1o2/70, 71, 73-816, Preventing the detonation of the fuze under y w og/gg 3 mature impact. This abort action can take place at any time subsequent to removal of the safety pin and prior [56] References Cited to the time the fuze is fully armed.

UNITED STATES PATENTS 9 Claims, 5 Drawing Figures 3.495.533 2/l970 Muller; ..'...l02/ 78 2,030,085 2/1936 Woodberry l02/78 ill 1; 31 :ll m- 12 11 1 1 J0 I v l 26 Il ,Q i l u -n 10 ge 1 12 c #111 l l 1 1.4 "1 2a I 122 1 1 I! 1 i J! 1 N 1) '1 #6 36 .--Ill 4 m d firing mechanism, an abort catch, and a detonating.

PATENTEDUEE 9 I912 SHEET 1 BF 2 Q K 0 MM hm mm y m u/ M iN h mzri 1 mawp M an A w n an ABORT MECHANISM BACKGROUNDOF THE INVENTION This invention relates generally to fuzes, and, more particularly to a safety fuze which includes an abort mechanism capable of preventingthe completion of the arming cycle of the fuze upon premature impact of the projectile or bomb.

Existing fuzes prevent firing upon premature impact by providing an arming delay. With this feature a fuze, on impact, will not fire immediately, but may ricochet and fire on a subsequent impact. This may or may not provide adequate time for safe separation between the aircraft and the bomb. .The bomb (and fuze) may also impact prematurely and not ricochet. The fuze would then arm subsequent to impact and faiLA fuze that aborts or stops all arming action on premature impact eliminates these potential hazards.

Other circumstances also require additional fuze safety. Some weapons are so effective that the risk of accidental release on aircraft takeoff or landing must be nullified. Area type weapons should also be safe to jettison over friendly territory. Existingfuzes do not provide sufficient safety for these release conditions. In the case of an external store with submunitions, the munitions or bombs may be released over the target, but one or more may inadvertently hang-up in the dispenser. Then. on the impact of aircraft landing, the

munition could skitter down the runway until the arming cycle is complete and then fire on the next impact it experiences. Jettisoning a dispenser with submunitions may result in the release of the munitions upon dispenser impact with the ground. The munition could then tumble free along the ground, arm after the set time and fire upon the next severe impact.

In the unarmed position a safety pin holds the arming pin of the fuze in its completely down position, so that the lower tip of the arming pin engages a stop hole in a rotor which forms an essential element of the instant invention. In the down position the arming pin prevents the rotor from leaving its unarmed position. The fuze further contains a plurality of weights and a push pin which, when the fuze is unarmed, are in their normal up" position. In the unarmed position an abort catch prevents the push pin from descending and in this posi- "tion the push pin is resting lightly on the top of a firing The fuze is the mechanism utilized for igniting or detonating the bursting charge of such a projectile, and

performs this function upon impact of the projectile with any substantially rigid object, such as the earth. Fuzes should be certain in action, safe in handling and using, free from deterioration in storage, simple in design and operation, and easy to manufacture and load. Someof these requirements, however, are conflicting, for example, safety features usually complicate the design of a fuze and therefore increase the difficulty of manufacture.

Heretofore, various fuze mechanisms have been employed to detonate a projectile upon impact, however, known impact-firing mechanisms have not satisfied the existing safety requirements for premature impact conditions or jettison fail-safe. For example, such devices generally required complex and expensive actuating mechanisms in order to incorporate therein the proper abort or safety means. Thus these fuzes became, contrary to fuze requirements, difficult to assemble, unsafe in handling and storage, and frequently operatively unreliable.

SUMMARY OF THE INVENTION The safety fuze of this invention incorporates therein an abort mechanism which overcomes all of the problems heretofore encountered and as set forth in detail hereinabove. v

The fuze of the instant invention is maintained in the unarmed position until the time of utilization.

mechanism. The extreme right tip or arm of the firing mechanism is located directly above a raised surface of the rotor. With the rotor in the normal or unarmed position, downward movement of the firing mechanism is therefore impossible. The inability of the firing mechanism from moving downward also prevents the weight from moving.

When the safety pin is removed, the arming pin moves upward under the force of a spring until it touches a borerider pin. In this position, the lower tip of the arming pin has lifted up, out of the stop hole in the rotor allowing the rotor to turn under the influence of a driving means around its axis about 40. The rotor stops turning when an indented portion thereof touches the side of the arming pin tip. With the rotor in this new position, the raised surface of the rotor is no longer under the tip of the firing mechanism arm which now is free todeflect downward if struck by the push pin. In this position the fuze of this invention'is now capable of aborting under any premature impact of the fuze. The abort function of this invention, however, is indepen-' dent of whether the arming pin is against the borerider pin, or whether it is in the full up position as when the borerider pin is released. When the fuze receives a substantial impact under either of the above mentioned conditions, the weights move down, driving the push pin through the abort catch. The push pin depresses the firing mechanism and the arm is pushed into a recess in the rotor. Since the abort catch is essentially a one-way clutch, it permits the push pin to be driven down, but will not allow the pin to come back up. The push pin, once it has been forced down, stays in this position, preventing the firing mechanism from lifting up. Therefore, should impact occur subsequent to removal of the safety pin and prior to release of the borerider pin, then upon release of the borerider pin the rotor can rotate only part way toward the armed position before the side of recess touches the firing mechanism arm and stops. This stops the rotor permanently, since the firing mechanism cannot retract upward due to the action of the abort catch.

The driving means of the rotor has an escapement mechanism thereon which determines the speed of rotation of the rotor. In this manner the abort function can take place not only at the time when the borerider pin is in position but also at any time between the removal of the borerider pin and the full rotation of the rotor to the armed position.

If the fuze of this invention has not aborted, due to premature impact, the 'normal arming function will:

of the fuze, permitting the rotor under the influence of' the driving means to rotate completely to the armed position. In the armed position a detonator located on the rotor is now positioned directly under the firing pin of the firing mechanism and also above a lead cup. Any impact now, rather than aborting the fuze, will cause one or more of the weights to move down depressing the push pin on the firing mechanism, causing the tip of the firing pin to strike the detonator. The detonator fires, initiating the explosive train of the bomb or projectile.

. It is therefore clearly evident that with the use of the instant invention a bomb or projectile receiving a premature impact, that is an impact before complete rotation of the rotor, will abort the fuze permanently. Therefore, by utilizing a driving means .for the rotor which is capable of completely rotating the rotor at a predetermined speed, no munition may fire upon impact or subsequent to impact if the aircraft is within the destructive range of the bomb at the time of impact. If, the aircraft is still in range before complete rotation of the rotor, and' an impact occurs,'the bomb will become a dud in the manner set forth hereinabove.

It is therefore an object of this invention to provide a fuze which is capable of aborting under any premature impact thereof.

It is another object of this invention to provide a fuze which is simple in operation and therefore certain in action.

It is a further object of this invention to provide a fuze which is economical to produce and which utilizes conventional, currently available components that lend themselves to standard mass producing manufacturing techniques. I

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appendedclaims.

DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of the fuze of this invention, partly in cross section, and in the unarmed position;

FIG. 2 is a schematic top view of the rotor and escapement mechanism of the fuze of this invention;

FIG. 3 is a sideelevational view of the fuze of this invention, partly in cross section, and with the safety pin removed;

FIG. 4 is a side elevational view of the fuze of this invention, partly in cross section, and in the abortive position; and

FIG. 5 is a side elevational view of thefuze of this invention, partly in cross section, and in the fully armed and detonating position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 of the drawing, the fuze of this invention is shown in its unarmed position. The fuze is made up of a housing 12 which is fixedly secured in any conventional manner within a bomb or projectile (not shown). Within the housing 12 is a pair of hollow compartments 14 and 16. In upper compartment 14 is located a portion of head 18 of arming pin 20, whilein the lower compartment 16 is located not only a portion of head 18 but also the tip 22 of arming pin 20. The

compression spring 26 is mounted in upper compartment 14 between outstanding elements 28 of the housing 12 and a flange element 30 fixedly secured to head 18. The safety pin 24 counteracts the force of spring 26 and when in place prevents upward movement of arming pin 20 into the positions shown in-FIGS. 3 -5. Any suitable bearing member 32 is located within compartment 14. Also located partially within compartment 14 is slideable borerider pin 34 which prevents complete upward movement of arming pin 20 when the safety pin 24 is removed. FIGS. 3 and 4 show borerider pin 34 in position against the top of head 18 of arming pin 20.

The remaining elements of this invention are'located I arming pin 20 and is in slideable relationship therewith.

Preventing push pin 44 from moving under normal conditions is a firing mechanism 48 upon which push pin 44 lightly rests. The abort catch 46 is made of a plurality of flexible elements having an aperture in the center thereof which under impact conditions will spread away allowing push pin 44 to move therethrough and depress firing mechanism 48. The firing mechanism 48 is fixedly secured at one end to a moveable member 49 which is mounted on housing 12. Firing mechanism 48 also has an aperture 50 therein which allows the tip 22 of arming pin 20 to protrude therethrough. Further mounted proximate the other end of firing mechanism 48 is a firing pin 52 and directly at the other end of firing mechanism 48 is an arm 54.

Making up an essential element of this invention is rotor 56. The rotor 56 is rotatably mounted proximate the bottom of.housing 12 as shown in FIGS. 1 and 3-5. The top view of rotor 56 is shown most clearly in FIG. 2. The succeeding description should be read in view of FIG. 2, with the remaining FIGS. 1 and 3-5 illustrating the rotor 56 in various positions of operation. The rotor 56 is rotatably mounted on pivot pin 58. The rotor itself is constructed of a plurality of surfaces, the first surface 60 having thereon a gear segment 62 and any suitable drive means such as spring 64.'The spring 64 being fixedly secured at one end to the rotor 56 and atthe other end to body 12. Slightly raised from surface 60 is second surface 66 which has recess 68 formed therein. Third surface 72 is slightly raised above surface 66 and contains therein recess portion 74 and stop hole 76. A detonator hole containing detonator 71 is located within a fourth surface 75 forming the top of rotor 56.

An escapement mechanism 78 (shown in FIG. 2) of conventional construction mates with gear segment 62 and slightly retards the rotation of rotor 56 under the tension of spring 64. Although an escapement mechanism is shown in FIG. 2 it should be realized that any type of retarding means may be utilized with this invention. It is this retarding means which determines the amount of time required for full rotation of rotor 56. The significance of the time of rotation of rotor 56 will be made apparent hereinbelow in the operation of this invention. It is this feature of the invention which allows the abortive action of the fuze to take place at any time after removal of safety pin 24 and prior to complete arming.

MODE OF OPERATION In operation, the fuze 10 of this invention is best described with reference to FIGS. 1 andv 3-5. FIG. 1 shown the fuze 10 in the completely unarmed position, as, for example, when being shipped. The safety pin 24 holds the arming pin in its completely down position, so that the lower tip 22 of the arming pin 20 engages the stop hole 76 in the rotor 56. This prevents the rotor 56 from leaving its unarmed position. The push pin 44 has not quite engaged the abort catch 46 and is resting lightly on the top thereof and on top of the firing mechanism 48. The extreme right tip of the firing mechanism 48 or firing mechanism arm 54 is directly above the raised surface 75 of rotor 56. With the rotor 56 in this position, downward movement of the firing mechanism 48 is impossible. In this position the firing mechanism 48 also prevents the weights 38 from moving downward.

Referring now to FIG. 3 the fuze 10 has the safety pin 24 removed. This allows the arming pin 20 to move upward about 0.080 inch until it touches the borerider pin 34. In this position, the lower tip 22 of the arming pin 20 has lifted up, out of the stop hole 76 in the rotor 56, allowing the rotor 56 to turn about 40 around axis 58 by the action of spring 64. The rotor 56 stops turning when the side of recess portion 74 touches the (left) side of the arming pin tip 22. With the rotor 56 in this new position, the raised surface 75 of the rotor 56 is no longer under the firing mechanism arm 54, which now is free to deflect downward if struck by the push pin 44.

The fuze 10 is now capable of either (1) aborting under any premature impact or (2) moving to the fully armed position. The abort function of fuze 10 can take place at any time after removal of safety pin 24, that is, any time until full rotation of rotor 56 to the armed position shown in FIG. 5. This means that the abort function is independent of whether the arming pin 20 is against the borerider pin 34 (as in FIG. 4) or whether it is in the full up" position (not shown in FIG. 4). The type of escapement mechanism 78 and spring 64 utilized in this invention varies in accordance with the desired speed of rotation necessary for rotor, 56. Usually the full rotation of rotor 56 takes place at the time calculated that the delivery aircraft will be out of the destructive range of the bomb. In this way any impact on the bomb before full rotation of rotor 56 (or during the aircrafts presence in destructive zone) will abort the bomb and render it useless.

With the safety pin 24 removed, under any substantial impact, the weights 38 move down, driving the push pin 44 through the abort catch 46 (shown in FIG. 4). The push pin 44 depresses the firing mechanism 48 and therefore the arm 54 into a recess 68 in the rotor 56. Since the abort catch 46 is essentially a one-way clutch, it permits the push pin 44 to be driven down, but will not allow the pin 44 to come back up. The push pin 44, once it has been forced down, stays in this position,

preventing the firing mechanism 48 from lifting up. The rotor 56 can now rotate only part way toward the armed position before the side of recess 68 touches the firing mechanism arm 54. This stops the rotor 56 permanently, since the firing mechanism arm 54 can not retract upward.

If the fuze 10 has not aborted, due to premature impact, the normal arming function will take place. Referring to FIG. 5, once the borerider pin 34 has retracted out of the way, the arming pin 20 moves up against the top of the fuze 10, permitting the rotor 56 to rotate completely to the armed position (see FIG. 5). The detonator 71 is now directly under the firing pin 52, and also above the lead cup 80. Any impact now will cause one or'more of the weights 38 to move down depressing the push pin 44 down on the firing mechanism 48, causing the firing pin 52 to strike the detonator 71. The detonator 71 fires, initiating the explosive train. This completes the intended function of the fuze.

Although the invention has been described with: reference to particular embodiment, it will be understood to those skilled in the art that the invention is capable of a variety of alternative embodiments within the spirit and scope of this invention.

We claim:

l. A fuze comprising a housing, an arming means, said arming means being slideably mounted within said housing, a removable safety bolt, said safety bolt being capable of holding said arming means in the unarmed position, an actuating means having at least one weight rotatably mounted in said housing and a push pin operably connected to said arming means, an abort catch fixedly secured to said housing and in operative relationship with said actuating means, a firing mechanism moveably mounted in said housing, and a detonating means moveably mounted in said housing and positioned adjacent said arming means and said fir ing mechanism, whereby, in said unarmed position, said arming means is so positioned as to prevent the movement of said detonating means and said push pin rests lightly on said firing mechanism.

2. A fuze as defined in claim 1 wherein said detonating means comprises a rotor, said rotor having therein a detonator, a stop hole and at least one recess and a drivemeans operably connected to said rotor.

3. A fuze as defined in claim 2 wherein said arming means comprises an arming pin and a biasing means whereby, in the unarmed position, one end of said arming pin protrudes into said stop hole of said rotor in order to prevent movement thereof.

4. A fuze as defined in claim 3 wherein said firing mechanism has a firing pin and an arm thereon whereby upon removal of said safety bolt said arm is capable of engaging the recess of said rotor.

5. A fuze as defined in claim 4 wherein an escapement mechanism is operably connected to said rotor to the retard the movement thereof.

6. A fuze as defined in claim 5 wherein said drive means is a spring.

7. A fuze as defined in claim 6 wherein said rotor is rotatably mounted in said housing.

8. A fuze as defined in claim 7 wherein said abort catch has an aperture therein through which said push pin is capable of moving in only one direction.

3,706,282 a 7 9. A fuze as defined in claim 8'wherein a borerider pin is located adjacent said safety bolt and in operative relationship with said arming pin.

I t t t 

1. A fuze comprising a housing, an arming means, said arming means being slideably mounted within said housing, a removable safety bolt, said safety bolt being capable of holding said arming means in the unarmed position, an actuating means having at least one weight rotatably mounted in said housing and a push pin operably connected to said arming means, an abort catch fixedly secured to said housing and in operative relationship with said actuating means, a firing mechanism moveably mounted in said housing, and a detonating means moveably mounted in said housing and positioned adjacent said arming means and said firing mechanism, whereby, in said unarmed position, said arming means is so positioned as to prevent the movement of said detonating means and said push pin rests lightly on said firing mechanism.
 2. A fuze as defined in claim 1 wherein said detonating means comprises a rotor, said rotor having therein a detonator, a stop hole and at least one recess and a drive means operably connected to said rotor.
 3. A fuze as defined in claim 2 wherein said arming means comprises an arming pin and a biasing means wherEby, in the unarmed position, one end of said arming pin protrudes into said stop hole of said rotor in order to prevent movement thereof.
 4. A fuze as defined in claim 3 wherein said firing mechanism has a firing pin and an arm thereon whereby upon removal of said safety bolt said arm is capable of engaging the recess of said rotor.
 5. A fuze as defined in claim 4 wherein an escapement mechanism is operably connected to said rotor to the retard the movement thereof.
 6. A fuze as defined in claim 5 wherein said drive means is a spring.
 7. A fuze as defined in claim 6 wherein said rotor is rotatably mounted in said housing.
 8. A fuze as defined in claim 7 wherein said abort catch has an aperture therein through which said push pin is capable of moving in only one direction.
 9. A fuze as defined in claim 8 wherein a borerider pin is located adjacent said safety bolt and in operative relationship with said arming pin. 